The present invention relates generally to optical lens patterns and deals more specifically with a system and method or process especially suited for producing a unique pattern for a lens to be formed and then placed in an opening in a specific eyeglass frame wherein data characterizing the size and shape of the associated lens opening is provided to a pattern generator by a frame tracing apparatus coupled to the pattern generator.
Heretofore, the fitting of an optical lens in an associated eyeglass frame lens opening has generally relied upon the manufacturer of the particular style eyeglass frame to provide a nominally sized pattern for the opening. Such a pattern substantially replicates the shape of the lens opening in a representative eyeglass frame style and which pattern is typically used as a guide to control edging apparatus which peripherally contours or edges an optical lens blank to the shape of the lens opening. The patterns supplied by a manufacturer are usually identified and often kept in an inventory maintained by the user of such patterns.
Over the past several years, the proliferation of eyeglass frame styles and an increased number of eyeglass frame manufacturers have made it impractical for those operating from an inventory of patterns to order and maintain a pattern for each of the different eyeglass frame styles due in part to the increased space requirements necessary to store the greater number of different patterns. In addition, the process of selecting a given pattern from the inventory has become more difficult, inconvenient and time consuming especially in a large laboratory where a given pattern may be in use and not available for selection.
In smaller laboratories, it may be uneconomical or unreasonable to keep an inventory of patterns. In many of these cases a pattern is made either directly or indirectly from a frame or from a tracing of the frame lens opening. One such method for making a pattern utilizes a pattern blank that has a grid-like scale comprised of measured distances left, right, up and down from an origin printed on the blank. The origin of the grid coincides with the mechanical center of a blank and accordingly the mechanical center of a pattern made from the blank. In using such a blank, the mechanical center of the lens opening and the mechanical center of the blank must be properly aligned because a very small error of even a few tenths of a millimeter can result in an improper fitting lens. In addition, the horizontal axis of the lens opening in the eyeglass frame and the horizontal axis of the pattern must be maintained in a parallel relationship to ensure that the lens optics of a lens made from a corresponding pattern is positioned properly before the eye when the lens is in the eyeglass frame lens opening.
Once the frame lens opening is properly aligned horizontally and centered, the lens opening shape is transferred to the grid on the blank by tracing the lens opening with a tracing pen or other suitable marking device and the pattern blank is cut along the marked outline to produce the pattern. Any roughness in the pattern edge is usually smoothed with a file or wheel grinder.
A pattern made using the above described method cannot be assured to have the same size and shape as the frame lens opening unless compensation is made for the thickness of the tracing pen line and the depth of the eyewire groove among others Additionally there may be variations from eyeglass frame-to-eyeglass frame of the same style such as distortion caused by handling or heating of the frame, in which case a pattern produced for one frame lens open may not be suitable for another frame lens opening of the same eyeglass frame style.
The foregoing method for tracing a frame lens opening and producing an associated pattern requires a high degree of skill, is time consuming, often taking up to five minutes to trace and produce a pattern, and subjects an optical lens made from an incorrectly centered or dimensioned pattern to improper fitting in the lens opening and optical error. Furthermore, the above method is unsuitable for the economic production of large quantities of the same or different patterns.
It is a general object of the present invention therefore to provide a system for generating a pattern from a blank wherein the generated pattern replicates the size and shape of a lens opening in a specific eyeglass frame and with a further object that the data characterizing the size and shape of the lens opening be transmitted directly to a pattern generator from a frame tracing apparatus.
Another object of the invention is to provide such a system comprised of individual system components which are interconnectable for use in close proximity to one another at one location or as a network between a frame tracing apparatus and a pattern generator located remotely from one another at different locations.
Yet another object of the invention is to provide such a system for producing a large quantity of differently shaped patterns in a relatively short time period.
These general objects are achieved in accordance with the invention, and as described in more detail hereinafter, by a lens pattern making system having an eyeglass frame tracing apparatus for characterizing the size and shape of a lens opening in a specific eyeglass frame and means for transmitting the data to a pattern generator which may be located in proximity to or remotely from the tracing apparatus and which generator cuts a corresponding pattern from a blank fed to the generator.
Other objects and advantages of the present invention will be apparent from the following description of a preferred embodiment and the drawings.